Series-parallel control system.



E. R. OARICHOFF. SERIES PARALLEL CONTROL SYSTEM.

APPLICATION FILED APR-15, 1913.

l 1 1 0,039. P en ed Sgpt. 8, 19M

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Witnesses Inventor-z Eugene F?.Car*ichoffl P b I H Hisa ttc' rne g.

E. R. CARIGHOPP. SERIES PARALLEL CONTROL SYSTEM.

APPLICATION IILBD APR.15, 1913.

1,1 10,039. Patented Sept. 8, 1914. 2 SHEETSSHEET z.

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Witnesses Inventor":

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EUGENE GARICEUFF, F SCIl'ENEC-TADY, NEW YORK, ASSIGNOR T0 GENERALELECTRIC COMPANY, A CORIORATION OF NEW YORK.

SERIES-PARALLEL CONTROL SYTEM.

To all whom it may concern Be it lrnown that I, EUGENE R. CART- onorr, acitizen of thc United States, residing at rlchenectady, in the county ofischencctady, State of New York, have invented certain new and usefulimprovements in. Serieslarallei Control Systems, of which the followingis a specification.

This invention relates to the control of electric motors and moreparticularly to the control of a plurality of motors operating ir provedseries parallel control electric motors in which the eleclc switches forshort circuiting the re thetype in which the op gs are in the motorcircuit. the series parallel control sysen ctistoinary to employ asingle which-ls first connected in the of the rnolxarsin seriesposition'and "1 connected in series with the motors allel position. itis essential that the switches shall d 21 open upon. being; denergizedbefore it llel connections are made, otherwise tors may be connectedincircuit with tie protecting resistance. This diiliculty issometimesoveroonie by the use of interlocking contacts for insuring theproper sequence or operation.

I in carrying out my invention I employ a resistance for the motors inthe series posi tion which is separate and distinctfrom the it istsnceemployed in the parallel position of the motors. The resistanoeis shortcircuited b the electromagnetic switches and then is t short circuitedwhile the other resistances are connected in circuit with the motors inthe arallei position. With my va.rrangemem". toe motors go through thecomplete cycle from the series to the par allel" position employingelectromagnetic switches having operating windings in the motor circuitfor short circuiting all ofthe resistances, without opening the motorciroiiit in making the transition, and the use of interlocking contactson the resistance switches may be entirely dispensed with.

@ther objects and purposes of in" ,lnvention will appear in the courseiii-g specificationin which 1 have shown my Specification of LettersPatent. Application filed April 15, 1913.

on what is known as the series parallel sysof the objects of myinvention is to Viith this arran e of the' follow- Patented Sept. 8,1914. Serial No. 761,241.

invention embodied in concrete form for purposes of illustration. 4

in the accompanying drawings, Figure 1 illustrates one form of myinvention, and Fig. 2 illustrates a modification thereof.

Referring to Fig. l of the drawings, A and A represent the armatures oftwo motors to be controlled and F. F the series fields of the motors.ii, R, R represent the sections of resistance which are to be con ncctedin circuit with the motor in the series position and are known as theseries resistance. R R and R are sections of resistance to be connectedin series with the a-rmatures A and A respectively, in the parallelposition. S and S are the two electromagnetic switches for shortcirouiting the resistance while similar switches S S 5* and S shortei'rcut the resistances R and PM respectively. The particularconstruction and arrangement of these electromaga netic switches formsno part or my present. invention, teristic features of these switchesare of importance in the operation of my system.

,These switches have their operating windings in the motor circuit andhave the characteristic that they are held in the open QOSl'tlOY-l whenthe current relatively high and (h. not close until the current falls toa predetermined value.

The particular form of switch which is diagriumnafically illustrated inthe drawing is covered by a prior application of Edwin J. liiurphy.Serial No. (108,652, filed Febi ary 15, I911. 1

8 and (T are two contactors of the. ordi nary type for controlling themotor circuit. These contactors are controlled by the Inaster controllerM, contactor B being energized in the first position and contactor O inthe second troll'er.

D represents an electromagnetic switch for changing the connections themotors,

from series to parallel. The particular construction of this switchforms no part of my present invention but is coveredby a separateimplication filed by me, Serial No. 755,399, filed March 2 1913. Thisswitch consists of a magnetizing winding 1O adapted to be connected inthe motor circuit and a core or plunger 11 having pivoted thereto aswitch arm 12. The core 11 is connected although the charac position ofthe master con-f to the central point ofthe switch arrh 12 and thelatter cooperates at either end with the contacts 13, 14:; A spring 15presses the left hand end of the lever into engagement with the contactI l. ,lVhen the winding is energized the core is raised and with it thelever 12. During the first portion of the movement, the contz ct it actsas a fulcrum forthe lever until the right hand end of 10 the contact isbrought into engagement with the contact 1.3. When the engagement ismade'with the contact 13 the latter becomes the fulcrum so that furthermovement of the core. compresses the spring 15, and moves the 15 lever-l2 out; o;fi engagement with the con- 9 "3; h he circuit of the winding10 is controlled by contacts]: .T which operates in the samemannergaslthe icontactors, S, S, S 800.,

f 29, with the exception that the moving contact is .notconnectedwiththe operating winding but is insulated from the switch structurenzihe switch, therefore, is held 0 en when ecurrent is high and closed wen I the ,ou rrent falls to apredetermined value.

The,, -r'vindingof this contactor 1s ener zed t open by the nch s sothat even thoughthe'. resistgnceisall cut out and the current has fallenton predetermined value, the contactor T will ..not close to estghli-shthe llel.

position untilfthe master 'oh trol er has. 40 movedztothe third positlonand electromafi;

net '17 is e'nergiz which attracts the late 16 and moves it against thetension of sprin f 16 to release the.;contact of the contactor As thusconstructed and arranged the operationof my system is as follows,assuming the Part r master controllefihgs moved into the first positiona, contactor 'B will be energlzgdy thereby closing the motor circuitfrifi the 1 botrolleyto the contacts of contactor B, re-

sistances R, armature A, field F, throu h the contact 14 and lever 12 ofswitch I), armature A and field F to ground. In this first position ofthe master controller, therefore, the motors are in series with all theseries resistance in circuit. When the master controller is moved to theposition b the contactor C. is energized which upon closing shortcircuits the first section of resistance so B through the operatingwinding of the switchS. The cutting out of a section of re sistance Itcauses rush of current through the motor circuit a d winding of theswitch S. All the switches S are constructed, in a '55 manner now wellunderstood, so that they the position shown. When thewill not close atthe first rush of current but only after the current has dro pod to apredetermined lower value. W en, however, the motors speed up so as toreduce the'current to a predetermined value the. switch S will close,thereby short circuiting the sec- 1 0nd section of resistance It andconnecting the oper'atin winding of the switch S in circuit. In likemanner, when the switch S. closes the last section of resistance R isshort circuited through the winding of the contactor T. The two motorsare now connect,-

cd in series through the contacts of the contactors B and G, S and S,and through the winding of the contactor T. If new the master controlleris moved into the-position c the. wire leading to the electromagnetg,'17will be connectedto trolley so that the latch 16 will be moved toreleasethe contact of the contactor T, which will therefore close ea '86 soonas the .current in the motor circuit drops. to '9, predetermined valueand therebyclose. the clrcuit' of the winding 10 of parallel switch D.The winding 10 being energized, the parallel connection of-the motorswill first be made at the contact 13, and the series connectionthen'brok'en at the contact/i4.

The motor circuit now divides into two par.- allel paths, one leadingfrom trolley through the contacts of the contactors B, C, S, .S' and?or? the winding of contaetorf T, armature A,

field F, contacts of contactor; T, winding 1D} of switch D, thencethr'ou h the winding ofii" switch S. and resistances 2 to ground,-,and.theother leading'throu h the contacts. o'flrloo contactor B,resistances it B to thewind in; of the switch S contact 18, armature A"and field F to ground. It will be noted [that the current to motor A isstill supplied through the contacts of the series switches 195 S S sothat the latter must be maintained in closed position. In other words,successful operation does not depend u on the open' 0 the switches S andS-. he first rush hfi current upon connecting the motors in paral- 101causes the switches S and S to hold open until the motors speed up andreduce the current, whereupon the switches S, and

'sfi close and short circuit the first section of\-resistance B and R?respectively In H5 like manner switchesS and S close and short circuitthe last section of resistance; 'thejreh connecting the two motors inparsllel wit all resistances short circuited.

In Eig.- 2, I have shown a modified form of my invention in which one ofthe parallel resistances is also used in series. In order to bring aboutthis result the arrangement of the switchesf'B f11151 0, correspondingto the arrangement ot-sviitchea B and .G of 120 which are closed,whenthe switch 010508. 30

a, a mess With this arrangement one of the switches for controlling theresistances R is dispensed with, since the function is accomplished by asecond operation of the switch B The operation of this form oi myinvention is as follows: When the master controllcr M is moved to thefirst position. the contactor B is energized through the interlockingcontacts 19 of the contactor G. This closes the motor circuit from therolley through the contacts of the coutactor B, through the resistanceR, thence through the resistances it, armature A, field i con tact-1430f the parallel switch D, armature A, field F to ground. lVhen thecontroller is moved to the second position shown at I), contactor C isenergized which closes the interlocking contacts 18 and opens theinterlocking contacts 19 to decnergize the contactor B. The closing ofthe switch C short circuits the resistance R and completes a circuitfrom trolleythrough the contacts of contactor C, through the winding ofswitchS, resistance R, armature A, field l contact 14, armature A, fieldF to ground. The remaining sections of resistance R are cut out ofcircuit as described above. When the controller is moved to the thirdposition 0 the parallel switch D closes as betore, the connection of themotors being as follows: From the trolley through the contacts of thecontactor C, through the winding of contactor S, thence through twopaths, one through the. contacts and windings of the switches S and Scontactor T, armature A, field F, thence to the contacts of contactor T,winding of parallel switch D to the switch S, resistances R to ground,

while the other path is fromthe winding of the switch S, through theresistances R, winding of the switch S contact 1.3 of switch D, armatureA, field F, to ground. The first rush of current upon connecting themotors, in parallel causes the switches S and S to hold open until themotors speed up to reduce the current, whereupon these switches closeand short circuit the first section of resistance R and R respec;tively. When the switch S closes it short circuits the section ofresistance B through the winding of'switch S and when the current dropsto a proper value the switch S will close and short circuit the secondsection of resistance R The closing of the switch S closes theinterlocking contacts 20 which completes a circuit through the wires 21and 22 to the contactor B independently of the contactor C, The closingof the contactor B short circuits the second section of resistance R andplaces the two motors in parallel across the line. Contactor B,therefore, serves the double purpose of closing the motor circuit in thefirst position of the master controller and of acting as a resistanceswitch to cut out section of resistsigned to break current.

R in the last position of the master auce' controller. The interlock 18on contactor C insures that the two controller's B, and C will both dropout at the same time when .the controller is returned, therebypreventing the current from being broken on some of the other contactorswhich are not do Aside from the use of? the resistance R in the seriesposition this system operates practically the same as the system shownin Fig", l. The advantage of the use of this resistance in the seriesposition that a very slow speed may he obtained in the first position ofthe master cos'itrollcr without unduly increasing the amount ofresistance.

' While it have described my invention as emho-died'in concrete form andasoperating in a specific manner for purposes of illustration, it shouldhe-understooelt'hat i do not limit my invention thereto, since variousmodifications thereof will suggest themselves to those skilled in theart without departing from the spirit of my invention, the scope ofwhich is. set forth in the annexed claims. lVhat I claim as new anddesire to secure by Letters Patent of the United States, is' 1. In aseries parallel control system, a. pair of electric motors,electromagnetic means for connecting said motor in series or inparallel, a resistance for the motors in the series position, additionalresistances one for each motor in the parallel position, and

electromagnetic switches having their operating windings in the motorcircuit for controlling said resistances.

2. In a series parallel control system, a pair of electric motors,resistances for the motors, electromagnetic witches having theiroperating windings in the motor circuit for short circuiting saidresistances, and means whereby said motors are connected first in seriesand then 'in parallel with a resistance in circuit in each positionwithout opening the motor circuit.

3. In a series parallel control system, a pair of electric motors, aseries resistance, a master controller, means controlled thereby forconnecting said motors and resistance in series with each other,electromagnetic switches having their operating windings in the motorcircuit for cutting ,said resistance out of circuit, means forconnecting the motors in parallel through the closed contacts of saidresistance switches, a resistance in series with each motor in theparallel position, and electromagnetic switches having their operatingwindings in'the motor circuit for cutting out said resistances.

4. In a series parallel control system, a pair of electric motors, aresista'ncefor the motors in the series position, a resistance for" eachmotor in the parallel position, electromagnetic switches having theiroperating windings in the motor circuit for short cir- 'euiting saidresistances, and means whereby parallel with a resistance in series witheach motor without openin the motor circuit.

5. In a series para lel control system, a pair of electric motors, aresistance for the motors in the series positiom a resistance for eachmotor in the parallel position, electromagnetic switches having theiroperating windings in the motor circuit for short cirouiting saidresistances, and an electromagnetic switch for connecting the motors inparallel with a resistance in series with each motor through the closedcontacts of the series resistance switches.

6. In a series parallel control system, a pair of electric motors, aseries resistance, a

master controller means controlled thereby for connecting sald motorsand resistance in series with each other, electromagnetic switcheshaving their operating windings in' the motor circuit for shortcircuiting said resistance, a resistance for each motor in the parallelposition an electromagnetic switch for connecting the motors in paralleleach with a resistance in circuit therewith through the closed contactsof the series re sistance witches. v

In witness whereof, I have hereunto set my hand this 14th day of April,1913.

Y EUGENE R. GARICHOFF.

Witnesses;

Y BENJAMIN B. HUL

IIELEN ORFORD.

